The canine parainfluenza virus type 2 (CPiV-2) plays a decisive role in acute infections of the upper respiratory tract of the dog, which are summarised under the term “kennel cough”. In kennels or similar facilities, antibodies can be detected in up to 70 % of all animals.
Infections with CPiV-2 alone usually only lead to mild or clinically inapparent courses of disease. Only in the case of secondary infections with other viruses (especially canine adenovirus-2 / canine herpesvirus-1), bacteria (Bordetella bronchiseptica, streptococci, staphylococci, etc.) or mycoplasma, as well as poor housing and/or hygiene conditions, do the known severe courses of the disease develop.
Bovine parainfluenza virus 3 (PI-3, BPIV-3) plays an important role in acute respiratory diseases in cattle, especially in the development of the infectious factor disease enzootic bronchopneumonia. Monoinfections cause only mild symptoms or are clinically inapparent. Only through secondary infections with other viruses (e.g. bovine adenovirus), bacteria (pasteurella, mycoplasma) and resistance-reducing factors (cold weather, stress, poor stable hygiene) do severe disease symptoms develop in the form of endemically occurring bronchopneumonia. The virus is excreted with the nasal secretion and is transmitted aerogenically. The clinical picture is characterised by fever, respiratory problems and salivation. About 5 % of the animals die within 3 – 4 days. Various vaccines are available, but reinfection can occur after a few months.